1. Technical Field
The present invention relates, in general, to traffic engineering applied to a multiprotocol label switching (MPLS) system and, more particularly, to a data structure for implementation of traffic engineering and a storage medium for storing the same.
2. Related Art
With the demand for Internet access rapidly increasing since the beginning of the 1990's, the need to improve quality and reliability of service has placed a burden on Internet networks, forcing them to depart from the provision of large-scale (or high-speed) and best-effort services, which are conventional key network attributes. Recently, as the Internet has served as the infrastructure of economic activities, Internet service providers (ISPs) have particularly focused on the quality of service (QoS). According to such a trend, ISPs have used an MPLS over ATM (MPOA) system employing an asynchronous transfer mode (ATM) network, or they have added more resources than are desirable onto Internet networks, in order to meet the demand for resources on networks and to stably provide high-quality Internet services. Nevertheless, it is not easy for ISPs to cope with rapidly increasing network traffic. It is also the current reality that the number of users requiring services of high quality is on a continuously increasing trend. As a result, ISPs have given attention to an Internet protocol (IP) traffic engineering technology capable of providing an additional service for efficiently using limited network resources in such a manner that IP traffic is efficiently distributed according to the amount of use, and is then assigned differential resources by services. This system has resulted in the advent of traffic engineering based on an MPLS system.
Unlike existing Internet networks that are of a nonconnection-oriented type, the MPLS system is adapted to control IP traffic by setting up a label switched path (LSP) or connection-oriented logical channel, and by directing the IP traffic to the set-up LSP. The MPLS system has an explicit routed LSP (ER-LSP) setup function and flow categorization function for controlling the allocation and flow of one resource to each traffic. This enables control of IP traffic and the provision of differential services to subscribers, which were previously unable to be conventionally achieved.
The MPLS system typically employs two signal protocols, a constraint-based routing-label distribution protocol (CR-LDP) and resource reservation protocol-traffic engineering (RSVP-TE). Both of these two signal protocols are used for the purpose of transferring label information for label swapping, and the equipment employing them provides an ER-LSP setup/release function performed by an operator, and an LSP protection function for bypassing traffic to an alternate path upon occurrence of a fault after the alternate path is predefined for LSP protection. However, such equipment has a limitation in its ability to provide a variety of additional services, because a forwarding equivalence class (FEC) is determined depending on a destination address in an IP packet header. This makes it difficult to sufficiently reflect rapidly varying requirements of users for a variety of services.
On the other hand, in order to provide the network subscriber with a service of high quality using a traffic engineering function in an MPLS system, the MPLS system has to input FEC information of a subscriber, path information and service associated information. Such information may generally be entered in the MPLS system through any one of the following two exemplary methods. In a first method, respective information is classified according to predefined items and then sequentially entered in the system. In a second method, respective information is configured in the form of entries, which are defined by an operator. Traffic engineering using the MPLS system is then implemented on the basis of the entries.
The above-mentioned methods have a critical disadvantage in that subscriber FEC information, path information and QoS information are not modeled in detail, thereby making it difficult to appropriately manage them and to provide a variety of high-quality services.